drivers: stepper: rename gpio_steppper_controller to h_bridge_stepper

rename gpio stepper to h bridge stepper
minor correction in stepper_stop, stepper_stop shall cancel all active
movements and should not be concerned about keeping the coils energized
or not, since that is a concern of a motion controller and not a stepper
driver.

Signed-off-by: Jilay Pandya <jilay.pandya@outlook.com>